1. Field of the Invention
The present invention relates to selectors for actuating bicycle gear mechanisms including hub gears or derailleur gears.
2. Description of the Related Art
EP-0 686 552 A2 discloses a rotatable grip for actuating bicycle gear shifts, in which the conversion of the rotational movement of the grip into a longitudinal movement of a control means is carried out in such a way that the control means is fastened to the grip, deflected in a helical manner about the bicycle handlebar or a sleeve encasing the handlebar, and guided in a longitudinal guide that is stationary in relation to the bicycle handlebar, at a sufficiently great distance, in the rotational direction of the grip, from the fastening of the control means to the grip. This means that the travel of the fastening point of the control means that is covered when the grip is rotated along a circular path is considerably greater than the travel of the control means in its longitudinal guide. The result is thus favorable conversion of wide angles of rotation at the grip into small longitudinal movements of the control means. The grip is fixed in the positions for the respective gear stages of the bicycle gear shift by a detent so that it is possible to vary the holding force and the necessary actuating force of the detent.
The above-mentioned rotary shift grip has a detent which must be oriented to the predefinitions in the respective gear mechanism of the bicycle. This condition leads to the situation in which different shift travels may result in the various gears, and individual gears may lie closer together and other gears may lie further apart from one another. Where the gears lie closely adjacent one another, shift stages may be skipped inadvertently if the rider does not pay close attention to shifting.
It is therefore an object of the present invention to provide an ergonomic selector which is easy to use and simple to manufacture.
Another object of the present invention is to provide a selector having approximately equally large shift travels, whose angles of rotation have a specific magnitude.
Still another object of the invention is to provide a selector having a mechanism which, on the one hand, permits correction of the total shift travel and/or the individual shift travels for the gear stages, while on the other hand, permits overshift travels of any magnitude for the individual gear stages.
In a presently preferred embodiment of the present invention, the selector not only produces approximately identical shifting steps, but it is also possible for the total shift travel to be varied if the pulling-in of the cable which is produced by winding the control cable onto the drum does not correspond to ergonomic requirements. It is therefore possible to achieve a step-up or step-down between the pull-in of the cable, on the one hand, and the movement of the actuating elements, on the other.
That is not the whole story, however: the design of the selector proposed in the present invention also permits an overshift travel to be produced for each gear stage or for all gear stages, which is particularly desired when shifting the chain from a respectively smaller to a larger sprocket. This means that, during shifting, the derailleur is briefly shifted somewhat further than necessary, in order to make it easier for the chain to xe2x80x9cclimbxe2x80x9d upward. The proposed selector permits an individual overshift travel for each gear stage, if this is necessary, and permits operation which fixes the respective position of the gear stages without a reverse rotational movement of the actuating elements.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims.